uml: use correct type in BLKGETSIZE ioctl

I found a type mismatch in UML that makes host block devices unusable as ubd
devices on x86_64 and other 64 bits systems (segfault of the mm subsystem):

In block/ioctl.c, the following lines show that the BLKGETSIZE ioctl expects
a pointer to a long:

	case BLKGETSIZE:
		if ((bdev->bd_inode->i_size >> 9) > ~0UL)
			return -EFBIG;
		return put_ulong(arg, bdev->bd_inode->i_size >> 9);

In arch/um/os-Linux/file.c, os_file_size calls it with an int.

The ioctl_list man page should be fixed as well.

Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index 6f92f732d253..c3ecc2a84e0c 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -320,7 +320,8 @@ int os_file_size(char *file, unsigned long long *size_out)
         }
 
         if(S_ISBLK(buf.ust_mode)){
-                int fd, blocks;
+                int fd;
+                long blocks;
 
                 fd = os_open_file(file, of_read(OPENFLAGS()), 0);
                 if(fd < 0){